1. Field of the Invention
The present invention relates to a field emission array with carbon nanotubes as an electron emitter source, instead of conventional micro tips. The present invention further relates to a method for fabricating the field emission array of the present invention.
2. Description of the Related Art
In recent years, many attempts have been made to adopt carbon nanotubes as an electron emitter source in electron emission devices, instead of metallic micro tips, because the carbon nanotubes are superior in durability and thermal stability with a low work function. For such triode-type electron emission devices with carbon nanotubes, the complicated fabrication process associated with thin film formation is considered a drawback. Additionally, there is a problem of generating impurity gas inside a packaged device during operation.
To solve the aforementioned problems, it is a feature of an embodiment of the present invention to provide a field emission array using carbon nanotubes as an electron emitter source, and a method for fabricating the field emission array, in which a nonconductive substrate with gates is built-in to a front substrate, and a rear substrate with cathodes and carbon nanotubes deposited on the cathodes, is combined with the front substrate assembly having the nonconductive substrate, so that the overall thin film formation becomes easy without causing generation of an impurity gas inside the field emission array during operation.
According to an aspect of an embodiment of the present invention, there is provided a field emission array comprising: a rear substrate assembly including a rear substrate; cathodes formed as stripes over the rear substrate; and carbon nanotubes formed on the cathodes at a predetermined distance; and a front substrate assembly including a front substrate; anodes formed as stripes over the front substrate; phosphors deposited on the anodes; a nonconductive plate having a plurality of openings separated by a predetermined distance corresponding to the distance between each of the anodes; gates formed as stripes perpendicular to the stripes of anodes on the nonconductive plate with a plurality of emitter openings corresponding to the plurality of openings in the nonconductive plate; and spacers for supporting and separating the nonconductive plate having the gates from the rear substrate by a predetermined distance, wherein the rear substrate assembly and the front substrate assembly are combined so that the carbon nanotubes on the cathodes project through the emitter openings at a predetermined distance from the gates.
In another embodiment, there is provided a field emission array comprising: a rear substrate assembly including a rear substrate; cathodes formed as stripes over the rear substrate; and carbon nanotubes formed on the cathodes at a predetermined distance; and a front substrate assembly including a front substrate; anodes formed as stripes over the front substrate; phosphors deposited on the anodes; upper and lower nonconductive plates each having a plurality of openings separated from each other by a predetermined distance corresponding to the distance between each of the anodes; gates formed as stripes perpendicular to the stripes of anodes on the lower nonconductive plate with a plurality of emitter openings corresponding to the plurality of openings in the nonconductive plate, wherein the distance between the gates and the carbon nanotubes is reduced; and spacers for supporting and separating the upper nonconductive plate from the rear substrate by a predetermined distance, wherein the rear substrate assembly and the front substrate assembly are combined so that the carbon nanotubes on the cathodes project through the emitter openings at a predetermined distance from the gates.
In still another embodiment, there is provided a field emission array comprising: a rear substrate assembly including a rear substrate; cathodes formed as stripes over the rear substrate; and carbon nanotubes formed on the cathodes with a predetermined distance from each other; and a front substrate assembly including a front substrate; anodes formed as stripes over the front substrate; phosphors deposited on the anodes; a nonconductive plate having a plurality of openings separated from each other by a predetermined distance corresponding to the distance between each of the anodes; gates formed as stripes perpendicular to the stripes of anodes over the nonconductive plate extending the upper sidewalls of the nonconductive plate which are exposed through the plurality of openings in the nonconductive plate; and spacers for supporting and separating the nonconductive plate having the gates from the rear substrate by a predetermined distance, wherein the rear substrate assembly and the front substrate assembly are combined so that the carbon nanotubes on the cathodes project through the emitter openings at a predetermined distance from the gates.
According to another aspect of the present invention, there is provided a method for fabricating a field emission array, comprising: forming a rear substrate assembly including a rear substrate; cathodes formed as stripes over the rear substrate; and carbon nanotubes formed on the cathodes at a predetermined distance; forming a front substrate assembly including a front substrate; anodes formed as stripes over the front substrate; phosphors deposited on the anodes; a nonconductive plate having a plurality of openings separated from each other by a predetermined distance corresponding to the anodes; gates formed as stripes perpendicular to the stripes of anodes on the nonconductive plate with a plurality of emitter openings corresponding to the plurality of openings in the nonconductive plate; and spacers for supporting and separating the nonconductive plate having the gates from the rear substrate by a predetermined distance; and combining the rear substrate assembly and the front substrate assembly so that the carbon nanotubes on the cathodes project through the emitter openings at a predetermined distance from the gates.
It is preferable that forming the front substrate assembly comprises: depositing a metal layer over the front substrate and patterning the metal layer into the anodes as stripes; depositing the phosphors on the anodes; forming the gates as stripes on the nonconductive plate; and combining the nonconductive plate having the gates with the front substrate having the anodes and the phosphors using spacers so that the nonconductive plate and the front substrate are separated by a predetermined distance. In this case, forming the gates as stripes on the nonconductive plate may comprise: forming a plurality of openings separated by a predetermined distance in the nonconductive plate; and depositing a metal layer over the nonconductive plate having the plurality of openings and patterning the metal layer into the gates as stripes having the plurality of emitter openings corresponding to the plurality of openings.
It is preferable that forming the gates as stripes on the nonconductive plate comprises: forming a plurality of openings separated from each other by a predetermined distance in a lower nonconductive plate; depositing a metal layer on the lower nonconductive plate having the plurality of openings and patterning the metal layer into the gates as stripes having a plurality of emitter openings corresponding to the openings in the nonconductive plate; and mounting an upper nonconductive plate having a plurality of openings on the lower nonconductive plate having the gates such that the plurality of openings of the upper nonconductive plate correspond to each of the emitter openings. Alternatively, forming the gates as stripes on the nonconductive plate comprises: forming a plurality of openings separated by a predetermined distance in a lower nonconductive plate; and depositing a metal layer by a spint method on the top and upper sidewalls of the lower nonconductive plate which are exposed through the plurality of openings, and patterning the metal layer into the gates as stripes having a plurality of emitter openings corresponding to the openings.